PHY - SECTION 1: (SIN... PHY - SECTION : (M. O PHY - SECTION II : (IN... CHEM SECTION I (SL. CHEMISECTION Question 3 An elevator platform is going up at speed 20 ms and during its upward motion a small ball of 50 R mass falling in downward direction strikes the platform elastically at a speed 5 ms! Find the speed (in ms-!) with which the ball rebounds. m 50 gm M20 m - 5 ms